package com.weishi.common.utils;

import java.math.BigDecimal;

/**
 * 计算2个经纬度之间的距离
 */
public class GPSUtil {

    public static void main(String[] args) {
        double lat1 = 31.839060610265;
        double lat2 = 31.838950610265;
        double lng1 = 117.15557449768;
        double lng2 = 117.15557449768;
        double mm = GPSUtil.GetDistance1(lat1,lng1,lat2,lng2);
        System.out.println(mm);
    }

    private final static double a = 6378245.0;
    private final static double pi = 3.14159265358979324;
    private final static double ee = 0.00669342162296594323;


    /**
     * DecimalFormat转换最简便
     * double 精确到2位小数
     */
    public static double fun2(double f) {
        BigDecimal b = new BigDecimal(f);
        double f1 = b.setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue();
        return f1;
    }

    //计算出来的结果单位为米
    private static final double EARTH_RADIUS = 6378137.0;//6378137.0; 6378.137

    private static double rad(double d) {
        return d * Math.PI / 180.0;
    }

    /**
     * 经纬度分-度转换
     * @return
     */
    public static double changeDate(double branch){
        int a = (int) branch/100;
        String str = String.valueOf(branch);
        str = str.replace(".","");
        str = str.replace(String.valueOf(a),"");
        long bb = Long.parseLong(str)/60;
        return Double.parseDouble(a+"."+bb);
    }

    public static double GetDistance1(double lat1, double long1, double lat2, double long2) {
        double[] dd1 = toGCJ02Point(lat1,long1);
        double[] dd2 = toGCJ02Point(lat2,long2);
        lat1 = dd1[0];
        long1 = dd1[1];
        lat2 = dd2[0];
        long2 = dd2[1];
        double a, b, d, sa2, sb2;
        lat1 = rad(lat1);
        lat2 = rad(lat2);
        a = lat1 - lat2;
        b = rad(long1 - long2);

        sa2 = Math.sin(a / 2.0);
        sb2 = Math.sin(b / 2.0);
        d = 2 * EARTH_RADIUS * Math.asin(Math.sqrt(sa2 * sa2 + Math.cos(lat1) * Math.cos(lat2) * sb2 * sb2));
        return fun2(d);
    }

    /**
     * GPS数据纠偏
     */
    /** WGS-84 to GCJ-02 */
    public static double[] toGCJ02Point(double latitude, double longitude) {
        double[] dev = calDev(latitude, longitude);
        double retLat = latitude + dev[0];
        double retLon = longitude + dev[1];
        return new double[] { retLat, retLon };
    }

    /** GCJ-02 to WGS-84 */
    public static double[] toWGS84Point(double latitude, double longitude) {
        double[] dev = calDev(latitude, longitude);
        double retLat = latitude - dev[0];
        double retLon = longitude - dev[1];
        dev = calDev(retLat, retLon);
        retLat = latitude - dev[0];
        retLon = longitude - dev[1];
        return new double[] { retLat, retLon };
    }

    private static double[] calDev(double wgLat, double wgLon) {
        if (isOutOfChina(wgLat, wgLon)) {
            return new double[] { 0, 0 };
        }
        double dLat = calLat(wgLon - 105.0, wgLat - 35.0);
        double dLon = calLon(wgLon - 105.0, wgLat - 35.0);
        double radLat = wgLat / 180.0 * pi;
        double magic = Math.sin(radLat);
        magic = 1 - ee * magic * magic;
        double sqrtMagic = Math.sqrt(magic);
        dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi);
        dLon = (dLon * 180.0) / (a / sqrtMagic * Math.cos(radLat) * pi);
        return new double[] { dLat, dLon };
    }

    private static boolean isOutOfChina(double lat, double lon) {
        if (lon < 72.004 || lon > 137.8347)
            return true;
        if (lat < 0.8293 || lat > 55.8271)
            return true;
        return false;
    }

    private static double calLat(double x, double y) {
        double ret = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * Math.sqrt(Math.abs(x));
        ret += (20.0 * Math.sin(6.0 * x * pi) + 20.0 * Math.sin(2.0 * x * pi)) * 2.0 / 3.0;
        ret += (20.0 * Math.sin(y * pi) + 40.0 * Math.sin(y / 3.0 * pi)) * 2.0 / 3.0;
        ret += (160.0 * Math.sin(y / 12.0 * pi) + 320 * Math.sin(y * pi / 30.0)) * 2.0 / 3.0;
        return ret;
    }

    private static double calLon(double x, double y) {
        double ret = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * Math.sqrt(Math.abs(x));
        ret += (20.0 * Math.sin(6.0 * x * pi) + 20.0 * Math.sin(2.0 * x * pi)) * 2.0 / 3.0;
        ret += (20.0 * Math.sin(x * pi) + 40.0 * Math.sin(x / 3.0 * pi)) * 2.0 / 3.0;
        ret += (150.0 * Math.sin(x / 12.0 * pi) + 300.0 * Math.sin(x / 30.0 * pi)) * 2.0 / 3.0;
        return ret;
    }
}
